Interhemispheric transfer of sensory and working memory information is dictated by behavioral strategy

The cerebral hemispheres process sensory information largely independently, yet coherent perception and behavior requires rapid interhemispheric communication. Which cortical area transfer information across hemispheres and what governs transfer location remains poorly understood. Here, we combined bilateral whisker-based texture-matching tasks with cortex-wide calcium imaging in mice to investigate the interhemispheric transfer of sensory and working memory information. Mice compared textures presented either simultaneously to both whisker pads or sequentially with a delay, thereby requiring the transfer of sensory or working memory content across hemispheres. Despite identical task demands, animals adopted distinct active or passive behavioral strategies that dictate the cortical location of interhemispheric transfer. Passive mice route both sensory and working memory information through the posterior lateral association cortex, whereas active mice rely primarily on bilateral barrel cortices. During delayed comparisons, active mice rapidly shift information to the contralateral barrel cortex, exhibit impatience, and display reduced performance, indicating that barrel cortices are suboptimal for transferring working memory. These findings identify behavioral strategy as a key determinant of interhemispheric communication and demonstrate a flexible, state-dependent routing of information across the cortex.